REL is the current fad in subs, at least until the next one comes along.
The solution with subs is to use subs. As in, more than one. Use four and no matter what they are you are practically guaranteed of excellent awesome bass like you never heard before.
This approach is called a Distributed Bass Array and relies on the facts that all subs (yes even REL!) create lumpy bass, moving the sub around doesn't change this it only moves the lumps around, you can't tell where subs are anyway because you can't localize such low bass. So the answer is to use lots of subs, so each one puts out less bass, but all together they add up to super smooth, even, and incredibly deep bass.
Use four and it hardly matters what they are, you will be impressed. Do a search and read, everyone who actually does it will confirm.
In terms of connections you want the subs to be additional. That is, continue to run L and R full range. Doesn't matter how the subs are connected. Speaker level is as good as line level. It imposes no additional load or harm on the amp. You can even use line-level only subs and run them off speaker level, just use a cheap Line Out Converter (LOC) you can buy at Parts-Express for $10.
My system for years was just like yours. Tube amp, great sound, just never had great bass. The bass now is awesome, no-apologies, SOTA bass. https://systems.audiogon.com/systems/8367
The solution with subs is to use subs. As in, more than one. Use four and no matter what they are you are practically guaranteed of excellent awesome bass like you never heard before.
This approach is called a Distributed Bass Array and relies on the facts that all subs (yes even REL!) create lumpy bass, moving the sub around doesn't change this it only moves the lumps around, you can't tell where subs are anyway because you can't localize such low bass. So the answer is to use lots of subs, so each one puts out less bass, but all together they add up to super smooth, even, and incredibly deep bass.
Use four and it hardly matters what they are, you will be impressed. Do a search and read, everyone who actually does it will confirm.
In terms of connections you want the subs to be additional. That is, continue to run L and R full range. Doesn't matter how the subs are connected. Speaker level is as good as line level. It imposes no additional load or harm on the amp. You can even use line-level only subs and run them off speaker level, just use a cheap Line Out Converter (LOC) you can buy at Parts-Express for $10.
My system for years was just like yours. Tube amp, great sound, just never had great bass. The bass now is awesome, no-apologies, SOTA bass. https://systems.audiogon.com/systems/8367